Preparation and characterization of aromatic polyamides from 4,4′-(2,6-naphthylenedioxy)dibenzoic acid and aromatic diamines

A new aromatic dicarboxylic acid, 4,4′-(2,6-naphthylenedioxy)dibenzoic acid ( 3 ), was synthesized by the fluoro-displacement reaction of p-fluorobenzonitrile with 2,6-naphthalenediol in the presence of potassium carbonate, followed by alkaline hydrolysis. A series of aromatic polyamides having inherent viscosities of 1.30–2.19 dL/g were prepared by the triphenyl phosphite activated polycondensation from the diacid 3 with sixteen aromatic diamines. Most of the resulting polymers were noncrystalline and readily soluble in a variety of polar solvents such as N,N-dimethylacetamide (DMAc) and N-methyl-2-pyrrolidone (NMP). Except for those polymers derived from p-phenylenediamine, benzidine, and 4,4′-bis(p-aminophenoxy)biphenyl, transparent, tough, and flexible films were cast from the DMAc or NMP solutions. The films had tensile strengths ranging from 70 to 91 MPa, elongations at break from 6 to 50%, and initial moduli from 1.35 to 2.32 GPa. The polyamides exhibit glass transition temperatures in the range of 178–300°C. Almost all polymers are stable up to 400°C, with 10% weight loss being recorded above 500°C, in air and nitrogen atmosphere.     

Studies of the autoxidation of phenols catalyzed by the cobalt(II) complex of disodium N,N′-bis(salicylidene)-ethylenediamine-5,5′ -disulfonate bound to colloidal anion exchange resin

To overcome mass transfer limitations which are usually encountered on immobilizing active catalysts, cationic latex particles were used as support for the cobalt(II) complex of disodium N,N′-bis(salicylidene)ethylenediamine-5,5′-disulfonate ( 1 ). The cationic latex 2 was prepared by emulsion copolymerization of chloromethylstyrene (m/p-isomer mixture 60/40) and divinylbenzene (m/p-isomer mixture) followed by treatment with trimethylamine. The latexbound catalyst from 1 and 2 was found to considerably increase the reaction rate of the autoxidation of 2,6-di-tert-butylphenol in water as compared with the conventional polymer-free system. Reaction products were identified as the oxidative coupling product 3,3′,5,5′-tetra-tert-butyldiphenoquinone (3,3′,5,5′-tetra-tert-butyl-4,4′-dioxo-1,1′-bicyclohexa-2,5-dienylidene) and 2,6-di-tert-butyl-1,4-benzoquinone. All reactions showed an induction period before the start of dioxygen consumption. The rate of autoxidation in the three-phase mixtures of water, latex particles, and phenol droplets was not affected significantly by the method of mixing. The reaction rate increased as the concentration of 1 increased. Increasing the partial pressure of dioxygen in the range between 0,25 and 1,0 atm (2,53. 10⁴ – 1,01. 10⁵ Pa) gave a small increase in rate. The colloidal latex catalyst from 1 and 2 showed some loss of activity after successive runs.     

Emulsion polymerization of styrene using a new series of rigid rod-like cationic surfactants

A series of pyridinium salts (PCX) N-substituted with an ω-(4′-methoxy-4-biphenylyloxy)alkyl group has been synthesized and used as surfactants in the emulsion polymerization of styrene. These molecules have an alkyl chain with an even number (X = 6, 8, 10, or 12) of methylene groups and bromine as counterion. For these molecules a typical behavior of colloidal electrolytes has been observed by conductivity measurements on water solutions and the critical micelle concentrations (CMC) determined by this technique are 2.14, 1.47, 0.214, and 0.0097 mmol for PC6, PC8, PC10, and PC12, respectively. Latices prepared with three components (water/styrene/PCX) were fairly stable showing in all experiments a monodisperse particle size distribution (1.01 to 1.1) with particle diameters from 70 to 160 nm. These results are compared with those obtained using dodecylpyridinium bromide (DPB) as the surfactant.     

Synthesis and properties of polyamides and poly(amideimide)s based on 4,4′-[1,4(or 1,3)-phenylenebis(isopropylidene-1,4-phenyleneoxy)]dianiline

The diamines 4,4′-[1,4(or 1,3)-phenylenebis(isopropylidene-1,4-phenyleneoxy)]dianiline (p- 3 and m- 3 ) were synthesized in two steps from the condensation of 4,4′-[1,4(or 1,3)-phenylenediisopropylidene]diphenol (p- 1 and m- 1 ) and p-chloronitrobenzene in the presence of K₂CO₃ in N,N-dimethylformamide (DMF), giving the corresponding bis(4-nitrophenoxy) compounds, followed by reduction with the hydrazine/Pd-C system. A series of aromatic polyamides, aliphatic-aromatic polyamides, and poly(amide-imide)s were prepared by the direct polycondensation of the diamines with aromatic or aliphatic dicarboxylic acids and phthalimide unit-bearing dicarboxylic acids in N-methyl-2-pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents. In addition, two series of polyamides were prepared from terephthalic acid or isophthalic acid and aromatic diamines with isopropylidene and/or ether linking groups between the phenylene units, and the structure-property relationships of these polyamides were studied. Almost all the resultant polymers were amorphous in nature and could be solution-cast into transparent, tough, and flexible films. Most of the polymers exhibited moderately high thermal stability. Thus, they are considered as new candidates for processable high-performance polymeric materials.     

The cyclo-copolymerization of diallyl compounds and sulfur dioxide, 5. Copolymerization of some 4-substituted 1,6-heptadiene derivatives with sulfur dioxide

Copolymers of sulfur dioxide with N-substituted 4-(1,6-heptadiene-4-yl)pyridinium chlorides and bromides ( 1 ) and N-substituted 4-(3-butenyl)pyridinium chlorides and bromides, and some other 1,6-heptadiene derivatives 3 substituted in 4-position were prepared. The effects of the copolymerization conditions on the conversions and viscosities of the copolymers were studied and their structures by elemental analyses, IR and ¹H NMR spectroscopy. The thermal stabilities of the copolymers were also examined.     

Synthesis of telechelics with furanyl end-groups by radical polymerisation with azo-initiators and network formation with unsaturated polyesters via Diels-Alder additions

New azo-initiators with two and four furanyl groups were prepared: N,N′,N″,N″′-Tetrafurfuryl 2,2′-azo-2,2′-dimethyldiglutaramide ( 2 ), tetrakis[2-(2-furoyloxy)ethyl] 2,2′-azo-2,2′-dimethyldiglutarate ( 4 ), bis[2-(2-furoyloxy)ethyl] 2,2′-azodiisobutyrate ( 6 ), and N,N′-difurfuryl-2,2′-azodiisobutyramide ( 9 ). The decay constants and the activation energies of the decomposition of the azo compounds were measured by thermogravimetric analysis. Radical polymerisations of styrene and some (meth)acrylates were performed under “dead-end” conditions. The telechelic oligomers were characterized by GPC and NMR spectroscopy, proving a furanyl functionality of nearly two or four. The kinetics of Diels-Alder reactions between the telechelics and the dienophils maleic anhydride and dimethyl maleate were measured under pseudo-first order conditions. Addition of the telechelics to an unsaturated polyester prepared from maleic anhydride and diols led to a solid material with network structure.     

Über polyarylenalkenylene und polyheteroarylenalkenylene, 14. Synthesen und charakterisierung von poly(thieno[2′,3′:1,2]benzo[4,5-b]thiophen-2,6-diylvinylenarylenvinylen)en,poly(4,8-dimethoxythieno[2′,3′:1,2]benzo[4,5-b]thiophen-2,6-diylvinylenarylenvinylen)en und einigen modellverbindungen

Wittig-reactions of thieno[2′,3′:1,2]benzo[4,5-b]thiophene-2,6-dicarboxaldehyde (8a) with “mono- and bis-Wittig-salts” 12a–c and 9a–c poly(thieno[2′,3′:1,2]benzo[4,5-b]thiophene-2,6-diylvinylenearylenevinylene)s 10a–c and some model compounds 13a–c were obtained. Analogous reactions of 4,8-dimethoxythieno[2′,3′:1,2]benzo[4,5-b]thiophene-2,6-dicarboxaldehyde (8b) gave the corresponding poly(4,8-dimethoxythieno[2′,3′:1,2]benzol[4,5-b]thiophene-2,6-diylvinylenearylenevinylene)s 11a–c and their model compounds 14a–c . Wittig-reactions of benzo[b]thiophene-2-carboxaldehyde (15) with “mono- and bis-Wittig-salts” gave model compounds 16a–c and 17a, c . A new synthesis of thieno[2′,3′:1,2]benzo[4,5-b]thio-phene (4) was worked out. 4,8-Dimethoxythieno[2′,3′:1,2]benzo[4,5-b]thiophene (7) and dicarboxaldehydes 8a and 8b were synthesized for the first time. The structures of all compounds were confirmed by elemental analyses, IR and electronic spectra, those of the model compounds additionally by mass spectra, and in case of sufficient solubility by ¹H NMR spectra. The electrical conductivities of all polymers and their model compounds were investigated.     

A novel synthesis and characterization of phenylacetylene end-capped poly(aryl ether sulfone) and poly(aryl ether ketone) oligomers

A series of controlled molecular weight poly(aryl ether sulfone) oligomers with benzophenone moieties at the chain termini were prepared. The two carbonyl groups at the chain ends were converted to ethynyl groups by using trimethylsilyldiazomethane/BuLi in tetrahydrofuran. Reactions of 4,4′-isopropylidenediphenol with 4,4′-difluorobenzophenone and 4-fluorophenylphenylacetylene as the end-capping reagent in N,N-dimelthylacetamide afforded the desired poly(aryl ether ketone) oligomers Both sulfone and ketone containing oligomeric polyethers undergo crosslinking reactions at elevated temperatures.     

Thermotropic liquid-crystalline aromatic-aliphatic polyimides, 4. Poly(imide-urethane-carbonate)s based on pyromellitdiimide and 3,4:3′,4′-biphenyldicarboximide

Main-chain types of thermotropic liquid-crystalline (LC) poly(imide-urethane-carbonate)s were synthesized by melt polycondensation of N,N′-bis(6-hydroxyhexyl)pyromellitdiimide or N,N′-bis(6-hydroxyhexyl)-3,4:3′,4′-biphenyldicarboximide with diphenyl hexamethylenedicarbamate and/or diphenyl hexamethylenedicarbonate. The poly(imide-urethane)s were also obtained from the dihydroxyalkylene diimide derivatives and hexamethylene diisocyanate by polyaddition. Yields and molecular weights of the resulting polymers tended to decrease with increasing urethane units. Differential scanning calorimetry (DSC) measurements, polarizing microscopic observations and powder X-ray analyses at various temperatures demonstrated that the carbonaterich copolymers comprising the 3,4:3′,4′-biphenyldicarboximide derivative formed a nematic mesophase. Temperature-dependent Fourier-Transform infrared measurements suggest that hydrogen bonding of urethane linkages affects the formation of LC mesophases.     

Synthesis,structure-property relations and lyotropic behavior of perfluoroalkyl-substituted para-linked aromatic polyamides

A series of perfluoroalkyl-containing para-linked aromatic polyamides based on trifluoromethyl-p-phenylenediamine and a mixture of trifluoromethyl- and pentafluoroethyl-substituted terephthalic acid have been synthesized. The polyamides were prepared by a low temperature solution polycondensation of aromatic diacyl chlorides with N,N′-bis(trimethylsilyl)-substituted aromatic diamines. The influence of these perfluoroalkyl substituents on thermal properties, solubility and lyotropic behavior is discussed. ¹⁹F NMR spectroscopy was utilized for molecular weight determination and for further examination of the polymer structure.     

New poly(amide-imide)s syntheses, 6. Preparation and properties of poly(amide-imide)s derived from 2,7-bis(4-aminophenoxy)naphthalene,trimellitic anhydride and various aromatic diamines

An imide ring-containing dicarboxylic acid, 2,7-bis[4-(N-trimellitoyl)phenoxy]naphthalene (1,1′,3,3′-tetraoxo-2,2′-[2,7-naphthylenedioxybis(1,4-phenylene)]di-1H, 3H-isoindole-5-carboxylic acid ( 3 )), was prepared by condensation of 2,7-bis(4-aminophenoxy)naphthalene (4,4′-(2,7-naphthylenedioxy)dianiline) and trimellitic anhydride (1,2,4-benzenetricarboxylic acid 1,2-anhydride). A series of new aromatic poly(amide-imide)s 5 containing bis(phenoxy)naphthalene moieties having inherent viscosities of 0,8–1,57 dL/g were prepared by direct polycondensation of this diimide-diacid 3 with various aromatic diamines using triphenyl phosphite and pyridine as condensing agents in 1-methyl-2-pyrrolidone (NMP) in the presence of calcium dichloride. Polymers 5 show excellent solubility in polar solvents such as NMP, and most of them could be cast into transparent and tough films. Measurements of wide-angle X-ray diffraction revealed that those polymer containing p-phenylene or oxyphenylene groups are partially crystalline. Amorphous members exhibit glass transition temperature in the range of 250–311°C. Thermal analyses indicated that these polymers are fairly stable, and the 10% weight loss temperature were recorded in the ranges of 526–575°C in nitrogen and 481–556°C in air.     

Reactive poly(2-vinyl-4,4-dimethyl-5-oxazoione) and poly[(2-vinyl-4,4-dimethyl-5-oxazolone)-co-(methyl methacrylate)]s. Synthesis,characterization and chemical modification with 4-methoxy-4′-(β-aminoethoxy)biphenyl

Poly(2-vinyl-4,4-dimethyl-5-oxazolone) ( P₀ ) and poly[(2-vinyl-4,4-dimethyl-5-oxazolone)-co-(methyl methacrylate)]s with increasing content of methyl methacrylate units ( P₁–P₄ ) were synthesized and characterized. NMR spectra were discussed in terms of monomer sequence distribution and tacticity effects. The reaction of 4-methoxy-4′-hydroxybiphenyl ( 1 ) with 2-ethyl-2-oxazoline was utilized to prepare 4-methoxy-4′-(β-aminoethoxy)biphenyl ( 3 ) through the intermediate 4-methoxy-4′-[(N-propanoyl)-β-aminoethoxy]biphenyl ( 2 ). The homopolymer P ₀ and two copolymers P ₂ and P ₃ were functionalized with 4-methoxybiphenyl side groups by reaction with 3 via a ring-opening process in N,N-dimethylformamide (DMF) or 1,2-dichloroethane. The resulting copolymers P₅–P₈ were characterized by ¹H and ¹³C NMR. The highest degree of functionalized units was obtained in DMF at 80°C.     

Thermotropic liquid-crystalline aromatic-aliphatic polyimides, 3. Poly(imide-carbonate)s composed of 3,4:3′,4′-biphenyldicarboximide

N,N′-Bis(ω-hydroxyalkyl)-3,4:3′,4′-biphenyldicarboximide (l = 3, 6) were prepared by a two-step reaction (via intermediates) of 3,4:3′,4′-biphenyltetracarboxylic dianhydride and ω-amino-alcohols. Polycondensation of dihydroxyalkyl derivatives of the 3,4:3′,4′-biphenyldicarboximide (l = 3, 6) and/or biphenyl with alkylene bis(phenylcarbonate)s (m = 3, 6) afforded poly(imidecarbonate)s with high molecular weights in high yields, which were characterized by FT-IR and NMR measurements and elemental analyses and showed good solubilities in organic solvents. The mesogenic properties of the polymers were evaluated by means of differential scanning calorimetry (DSC), observation in the polarizing microscope equipped with a hot stage and by means of powder X-ray diffraction. The DSC curves of the imide unit rich polymers without annealing only display glass transition steps. The curves after annealing, however, show some endotherms. The polarizing microscope observation and X-ray analyses indicated that the homo-and copolymers from the 3,4:3′,4′-biphenyldicarboximide derivative with longer methylene chains (l = 6) form nematic liquid-crystalline mesophases.     

Aldehydes and acetals based on acryl- and methacrylamides as potential monomers

Hydrophilic monomers containing aldehyde or acetal groups based on N-substituted amides of methacrylic and acrylic acid were prepared. The structure of these monomers prevents undesirable spontaneous intramolecular cyclization reactions of pendant aldehyde groups of the corresponding polymers. The following monomers were prepared: N-(2-formyl-2-methylpropyl)-N-methylmethacrylamide (3) , N-(2,2-dimethoxyethyl)-N-methylmethacrylamide (5a) , N-(2,2-dimethoxyethyl) methacrylamide (5b) and N-(2,2-dimethoxyethyl)-N-methylacrylamide (12) .     

Synthesis of new polynaphthalimidophenylquinoxalines and their copolymers

A series of novel polyphenylquinoxalines containing naphthalimide structures in the chain were prepared by reacting 3,3′-diaminobenzidine, 3,3′,4,4′-tetraaminodiphenyl ether and 3,3′,4,4′-tetraaminodiphenyl sulfone with the two new monomers of N,N′-bis(4-benzoylcarbonylphenyl)-4,4′-(1,3-phenylenedioxy)-di-1,8-naphthalenedicarboximide ( 3a ) and N,N′-bis(4-benzoylcarbonylphenyl)-4,4′-[isopropylidenebis(1,4-phenyleneoxy)]-di-1,8-naphthalenedicarboximide ( 3b ). The obtained polymers exhibit high decomposition temperatures, their T_g values being, however, below 300°C. Their solubility in common solvents, e.g. chloroform, is excellent, but their molecular weight is low. Higher molecular weight products were obtained by copolymerization of 3a, b with N,N′-bis(4-benzoylcarbonylphenyl)-1,8 : 4,5-naphthalenetetracarboxdiimide ( 3c ) yielding films and fibers with good mechanical properties.     

Enzymatic splitting of side chains in soluble polymers. The effect of length and structure of the side chain

A series of soluble polymers was prepared by copolymerization of the 4-nitrophenol ester of N-methacryloylated ω-amino acids ( 1a – i ), of N-methacryloyldiglycine ( 2b ), of 6-(N-methacryloylglycylamino)- and of 6-(N-methacryloylglycylglycylamino)hexanoic acid ( 3a and 3b ) with N-(2-hydroxypropyl)methacrylamide (HPMA). The resulting polymers contained roughly 3 mol-% of nitrophenol groups. Polymeranalogous reaction with 4′-nitro L-phenylalanineanilide ( 4a ) or with its N-glycyl and N-glycylglycyl derivates ( 4b and 4c ), yielded polymers which at the end of their side chain of various length and structure had a bond degradable with chymotrypsin. The rate of enzymatic hydrolysis was investigated as a function of the length and structure of side chain. It was found that in copolymers possessing side chains formed by ω-amino acid residues, the rate of hydrolysis increases with increasing length of the side chain. The rate of cleavage of the peptide bond has a maximum value for a spacer that possesses six methylene groups. With increasing length of the side chain the rate of hydrolysis again decreases. A similar dependence was observed for side chains formed by dipeptides of ω-amino acids and glycine. In copolymers with oligoglycine side chains, the rate of enzymatic hydrolysis also increases with increasing length of side chain. In other types of side chains formed by combination of hydrophobic and hydrophilic segments, a number of factors become operative which affect the rate of enzymatic hydrolysis and are very difficult to specify.     

Synthesis of mainly linear poly(dichlorophenylene oxide)s by thermal polymerization in solution

Thermal decomposition of bis(4-bromo-2,6-dichlorophenoxo)-(N,N,N',N'-tetramethylethy-lenediamiene)copper(II) complex in toluene, bis(4-bromo-2,6-dichlorophenoxo)(N,N-dimethyl-formamide)copper(II) complex in N,N-dimethylformamide and bis(4-bromo-2,6-dichlorophenoxo)(dimethyl sulfoxide)copper(II) complex in dimethyl sulfoxide was achieved at 70°C. 4-Bromo-2,6-dichlorophenol derivatives prefer 1,4-addition to 1,2-addition, leading to highly linear polymers irrespective of the substituted ligands. The complexes were characterized by IR spectroscopy and C, H, N elemental analysis. The characterization of the synthesized polymers were achieved by ¹H NMR, ¹³C NMR and IR spectroscopy. The highest polymer yield was obtained from the decomposition of bis(4-bromo-2,6-dichlorophenoxo)(N,N,N',N'-tetramethyl-ethylenediamine)copper(II) complex.     

Conducting polymers from anodic coupling of some N,N′-bridged 2,2′-bipyrrolyl monomers

Anodic coupling in CH₃CN + 0,1 M tetraethylammonium perchlorate of some 2,2′-bipyrrolyl monomers bridged by X groups at the N,N′-positions (X = ? CH?CH? ( 1 ), o-C₆H₄ ( 2 ) ? CH₂? ( 3 ), ? (CH₂)₂? ( 4 ) and ? (CH₂)₃? ( 5 )) produces conducting, α-coupled polypyrroles (from IR spectroscopy), containing 0,25–0,30 counteranions per pyrrole ring (from elemental analysis). The in-situ conductivity spans from values commonly found for N-substituted polypyrroles (4 ? 10^?3 S/cm for 5 ) to unusually high values (2,5 S/cm for 4 ). A linear correlation between redox potentials and log of conductivities of the polymers evidences the influence of the polymer electronic properties of charge transport.     

Error‐prone replication bypass of the imidazole ring‐opened formamidopyrimidine deoxyguanosine adduct

Addition of hydroxyl radicals to the C8 position of 2′‐deoxyguanosine generates an 8‐hydroxyguanyl radical that can be converted into either 8‐oxo‐7,8‐dihydro‐2′‐deoxyguanosine or N‐(2‐deoxy‐d ‐pentofuranosyl)‐N‐(2,6‐diamino‐4‐hydroxy‐5‐formamidopyrimidine) (Fapy‐dG). The Fapy‐dG adduct can adopt different conformations and in particular, can exist in an unnatural α anomeric configuration in addition to canonical β configuration. Previous studies reported that in 5′‐TGN‐3′ sequences, Fapy‐dG predominantly induced G → T transversions in both mammalian cells and Escherichia coli, suggesting that mutations could be formed either via insertion of a dA opposite the 5′ dT due to primer/template misalignment or as result of direct miscoding. To address this question, single‐stranded vectors containing a site‐specific Fapy‐dG adduct were generated to vary the identity of the 5′ nucleotide. Following vector replication in primate cells (COS7), complex mutation spectra were observed that included ～3–5% G → T transversions and ～14–21% G → A transitions. There was no correlation apparent between the identity of the 5′ nucleotide and spectra of mutations. When conditions for vector preparation were modified to favor the β anomer, frequencies of both G → T and G → A substitutions were significantly reduced. Mutation frequencies in wild‐type E. coli and a mutant deficient in damage‐inducible DNA polymerases were significantly lower than detected in COS7 and spectra were dominated by deletions. Thus, mutagenic bypass of Fapy‐dG can proceed via mechanisms that are different from the previously proposed primer/template misalignment or direct misinsertions of dA or dT opposite to the β anomer of Fapy‐dG. Environ. Mol. Mutagen. 58:182–189, 2017. © 2017 Wiley Periodicals, Inc.     

Über polyarylenalkenylene und polyheteroarylenalkenylene, 13. Synthesen und charakterisierung von poly (dithieno[3,2-b: 2′, 2′,3′-d]thiophen-2, 6-diylvinylenarylenvinylen)en und einigen modellverbindungen

From Witting-reactions of dithieno[3,2-b: 2′, 3′-d]thiophene-2, 6-dicarboxaldephyde ( 1 ) with “mono-and bis-Wittig-salts” of the benzene and thiophene series poly(dithieno[3,2-b: 2′,3′-d]-thiophene-2,6-diylvinylenearylenevinylene)s 3a—c and some model compounds 5a—c were obtained. Wittig-reactions of dithieno[3,2-b: 2′,3-d]thiophene-2-carboxaldehyde ( 6 ) with “mono-and bis-Wittig-salts” gave model compounds 7a—c and 8a, c . The structures of all compounds were confirmed by elements analyses, IR-and electronic spectra, those of the model compounds additionally by mass spectra, and in case of sufficient solubility by ¹ H NMR spectra. The electrical conductivities of all compounds and the thermooxidactive degradation of the polymers 3a, c were investigated.